Plumb-bob



I J. A. EWING AND E. J. McGOWAN.

PLUMB BOB. APPLICATION mm MAR. 5, 1919.

Patented Aug. 17, 1920.

UNITED STATESPATENT OFFICE.

JAMES EWING, 0F 8PBINGDALE, AND EDWARD J. MCGQW'AN, OI? TAZBIENTUM.

PENNSYLVANIA.

PLUMB-BOB;

Specification of Letters Patent.

Application filed March 5, 1919. Serial No. 280,690.

1 '0 all whom it may concern.-

Be it known that we, JAMEs EDWARD J. McGowan, citizens of the United States, residing at Springdale and Tarentum, respectively, in the county of Allegheny and State of Pennsylvania, have ining had to the accompanying drawings, and

to the letters and figures of reference marked thereon, which form a part of this spcciiication.

This invention relates to an improved plumb-bob.

a means whereby the pliimlrline may be wound about a spring-actuated drum installed within the body of the plumb-bob, and automatically rewind the said line. further object of the invention is to provide a means for adjusting the length of the plumb line and lock said line at any point along its length, and a further object is to adjust the several parts with relation to the plumb-bob proper, so that the point of the bob will maintain an accurate axial line with that of the plumb-line. With these and other objects in view, the invention consists in the details of construction and combina tion of parts, as will be fully described here inafter.

In the accompanying drawings Figure 1 is a sectional side view, partly in outside elevation, of our improved plumbbob, the same being constructed and arranged in accordance with our invention.

Fig. 2 is a side elevation, partly in section, the said section being taken at right-angles to that shown at Fig. 1.

Fig. 3 is a plan View tion removed.

Fig. 4: is a detailed sectional view of the winding drum or reel and its connected parts, showing the same detached from the body of the plumb-bob.

Fig. 5 is a side view of the same.

Fig. 6 is a view in perspective of the reel or drum shaft.

Fig. 7 is a face and outside view of the clamps which engage with the plumb-line, and

having the top sec- A. EWING and The object being to provide an implement of this character that will afford Fig. 8 is a face view and sectional eleva tron the nut used for holding the clamps 1n positlon.

To put our invention in practical form we first form the plumb-bob proper, in an upper 1, apd lower section 2, the latter being fitted with the usual) hardened conical. point 3, attached by means of a threaded shank 4. These sections are connected, the one with the other, by means of a threaded flange 6, formed integral with the lower section 2, and a corresponding threaded socket formed with the upper section 1. Each of these two sections 1 and 2 recessed at 5 and 5, in a manner that will admit the placing of a eentrally-located, verticallydisposed, flanged winding reel or drum 8, about which the plumb-line 15, is wound. This drum 8, is mounted loosely upon a horizontally-arranged shaft 10, said" shaft being formed with angular shouldered. ends 11, which fit into notches 1 1, formed in the threaded flange 6, of the lower section 2, in such man nor as to prevent said shaft from turning. Formed within the body of the drum 8, is a compiurtment, open at one side and said opening closed by a disk 9. This compartment contains a flatcoil spring 12, one end 12, oi which is attached to the inner periphery oi? the drum 8, and the other to the shaft 10, said. shah: being slotted (17) a portion of its length, for the double purpose of said spring connection and as a spring "frictional contact with. the disk 9, as a means for holding said disk in position. The threaded flange 6, of the lower section 1, is recessed at diametrical points 7, located opposite the drum 8, (see Figs. 2 and 8,) there-- by permitting the largest diameter drum to be used. The upper section 1, of the plumbbob is formed with a contracted neck 19, provided with a screwthread for the pur pose of attaching a screw cap 2(),said. cap being perforated to give the plumb-line 15, free passage therethrough, and an opening 21, formed vertically through said neck to the recess 5, of the upper section 1.. The upper portion of the latter mentioned opening 21, is conical in form, the larger diameter at the top, and adapted to engage with two clamps; said clamps, when together, (see Fig. 7,) comprise a flanged portion 22, formed with integral conic :i'rustums, the one 23, of greater diameter than the other 24i, and each. section. of the clamp provided with a shallow groove 25. Arranged intermediate of the flanges 22, of the clamp and the mouth of the opening 21, is a threaded washer or nut 26, having wrench openings 28, said nut being provided with a central tapering opening or" a greater diameter than thatof the larger conic frustum 23. This nut 26, when in position, will prevent the displacement of the clamps, should screw cap 20, be disengaged from the neck of the plumb-bob. The upper section 1, of the plumb-bob and the screw cap 20, are each formed with serrated bands 16 and 16,to facilitate the separation of the parts.

.The one end of the plumb-line 15, is attached to the drum 8, and the free end threaded through the opening 21, the clamp grooves 25, the nut 26 and screw cap 20. The tension is placed upon the coil spring by winding the plumb-line 15, about the drum 8, placing the shaft in its bearings 14, and withdrawing the line, removing the drum from its bearings, care being taken to prevent the shaft 10, from turning, and the line rewound upon the drum. This operation is repeated should more tension be de sired.

In operation. The screw cap 20, is loosened, thereby relieving the pressure of the clamps upon the p1umbline 15. A predetermined length of the plumb-line is witl1- drawn from the drum, and the screw-clamp tightened downward upon the clamps, forcing their ends 2st, against the conical walls of the opening 21, thereby clamping the line 15, and holding the same rigid in this position. By releasing the screw-cap 20, the plumbline will automatically rewind upon the drum 8.

It is obvious that slight changes may be made in the form of the clamps or other details of construction, or that the holding washer or nut may be dispensed with, without departing from the spirit of the invention.

Having thus described our invention, we claim I 1. A plumb-bob formed in two sections. the one attached to the other. said sections having a centrally-100ated recess formed within the body of the same, and an axiallydisposed opening having a conicatshaped mouth leading to said recess, a spring-actuated drum located within said recess, a stationary shaft carrying said drum. a coil spring connecting said drum and stationar shaft, a plumb-line attached to and wound upon said drum, ascrew-eap having a cent rat perforation connected to the neck of the plumbhob, a. means comprising conicalshaped clamps operated by said srrmv-rap, said clamps adapted to engage with the plumb-line and hold the same rigid at any point along its length and a means for confining said clamps in position.

2. A plumb-bob ha ring a centraltv-located recess, a spring-a -tuated winding drum arranged in said recess, a. plumb-line attached to said drum, said recess having an axially-located opening leading therefrmn, a perforated screw-cap closing said opening. clamps engaging with said plumhdine and operated by the contact pressure of said screw-cap, and a means comprising a washer or nut for confining said clamps in position.

In testimony whereof, we atlix our signatures in presence of two witnesses.

JAMES A. EWING. EDlVAltD J. Met-()WAY. \Vitnesses M. E. HARRISON, HARRY C. VALLEY. 

